Well, the boxster sat long enough... all winter actually, which lead to the battery dying and cracking all over the battery tray. Man it was a mess. To make matters worse, I was in a pretty bad accident months back and handicap enough that I wasnt walking for a while. Not a whole lot of opportunity to get to the porsche.
However, I've finally got my new battery in, and since I'm re-doing the stereo I opted for the Optima Yellowtop for that extra juice it's provided me in previous cars. It works well for the porsche because the more common models still have adequate cranking amps for the boxster (I couldnt put one in my truck because there just wasnt enough juice there) . It will also help out come winter because I really dont drive the car from november - march.
I have to say the battery fits real nice in there, although I really planned for the tolerances and it did just barely fit. The red top I had originally planned for was smaller than this yellow top. It also looks great sitting in there, although its obviously covered most of time time.
Why is this any different than the red top? Because the red top has a lip that goes all around the battery. The yellow top only has a lip front and rear (along the long-edges of the battery). This means you have to mount it from front and rear to get it to stay (without a strap at least) and the best way to do this is with a slight modification of the OEM tray and the included optimum battery mounts.
What I did is remove the porsche battery tray, and fit the yellow top under the lip thats in the long rear horizontal part of the tray. I could have used the optimum tray adapter but it was just too big and bulky. The factor tray lip holds the battery real nicely under there without having to use the fattening-adapter that optima provides with the battery. I then took the wedge (also included with the battery) and lined it up with the center cell on the battery. I cut a wedge out of the edge of the battery tray (the rounded portion in the front, dead center) and flattened the slag towards the inside of the tray. This gave me extra reinforcement to mount a bolt to.
Next I drilled through the folded slag and the bottom of the tray to accomodate a 2" long 5/16" bolt. This allowed me to bolt down the front of the battery while the lip in the tray held down the rear.
I had already put in a 12" positive battery lead before replacing the tray, but you have enough room to replace this if you do it after the fact. You will have to replace it, but not the length I've read elsewhere (30"). A 12-15" positive lead is fine. I couldnt find a 1g Red, so I settled for a "clear" just so there was some distinguishable characteristics. It doesnt matter, obviously through the fact that both OEM cables are black. Now for the battery tray:
The best way to get a battery into the porsche is to go ahead and step into the trunk so you arent fighting a leverage deficiency! You will find that there is not enough room to tighten a nut on the battery if you put the tray in first. You can, however, mount the battery and drop it in with the tray, while still having access to all 4 tray bolts that attach the tray to the car. This is how I got the battery in, knowing I could just remove the bolts later and pull the assembly if I had to. Others have done it without this obstacle, but they built a variety of mounts to accomodate this and they didnt look anywhere as clean as this install with the optimum parts. Most were also using red-tops, which have a lip around the entire battery. As mentioned, Yellow top has no lip on the sides, so you have to mount it front and back. The good news is, optimium has an easy-on/off handle that slides on and off the battery, so if you dont toss that you can get the battery out as needed later! And even then, you are just 4 bolts away from removing the battery.
It's a little trick manuevering the battery tray in while attached to the battery. The wedge adds about 1/4" to the thickness of the otherwise exact-fitting tray, so the best thing to do is angle the battery towards you and dip the wedge under the compartment lip. Then lower the rear battery into the compartment. You have some hoses there that might have their clamps in the way depending on how you orientate them. I rotated the clamps so nothing was protruding towards the battery, and problem solved. Tighten down your 4 bolts, step back and you'll notice that the battery is still centered nicely (if you lined it up with the center of the round front of the tray).
So, not counting the battery, the additional cost to get this in was 7.95 + tax for the battery cable. The battery included all the mounts, and I had the bolts. I put a lock washer on there to be safe as well, which I highly recommend any time you are relying on a lip and tightening from only one side. It looks real clean, and provides plenty of advantages over the old battery. I couldnt tell you if it is heavier than the OEM batteries or not, but I can say that this install keeps the battery centered like the original. It takes a little extra creativity since its less universal than the red-tops, but it goes in just as nicely as the OEM! Total project time: 30 min. I filed the edges of my cuts etc though and took my time, so Im sure it could be done faster!
When I finally started the car, it made all sorts of noises. I decided to just let it run for a while. Weird things happened, like the one-touch windows not working right away but later kicking in, and the brakes made a lot of noises for a while. I suppose the car is just chastizing me as it settles in. I'm going to take her out for a spin right now, since I've been dying to ever since I was bedridden! So nice that its warm out again... happy riding ;-)